Which statement is true about high-risk NSTE-ACS in terms of ECG findings compared with STEMI?

Which statement is true about high-risk NSTE-ACS in terms of ECG findings compared with STEMI?

• A. ST-segment elevation
• B. ST-segment depression of 0.5 mm or greater or dynamic T-wave inversion with pain
• C. No ECG changes
• D. Peaked T waves

Answer: (B)

The key idea is that high-risk non–ST-elevation ACS signals ischemia without the transmural injury that causes ST-segment elevation. On the ECG, this shows up as ST-segment depression of at least 0.5 mm or dynamic T-wave inversion, often accompanied by chest pain. These patterns indicate subendocardial ischemia and a higher risk of progression to myocardial infarction, which is why this finding is the best description for high-risk NSTE-ACS. ST-segment elevation is the hallmark of STEMI, not high-risk NSTE-ACS, so that option doesn’t fit. An ECG with no changes is possible in some ACS cases but doesn’t capture the high-risk ischemic pattern described. Peaked T waves point to electrolyte issues like hyperkalemia, not ACS patterns.

The key idea is that high-risk non–ST-elevation ACS signals ischemia without the transmural injury that causes ST-segment elevation. On the ECG, this shows up as ST-segment depression of at least 0.5 mm or dynamic T-wave inversion, often accompanied by chest pain. These patterns indicate subendocardial ischemia and a higher risk of progression to myocardial infarction, which is why this finding is the best description for high-risk NSTE-ACS.

ST-segment elevation is the hallmark of STEMI, not high-risk NSTE-ACS, so that option doesn’t fit. An ECG with no changes is possible in some ACS cases but doesn’t capture the high-risk ischemic pattern described. Peaked T waves point to electrolyte issues like hyperkalemia, not ACS patterns.